Air handling systems used to condition buildings or rooms typically include a structure having components designed to condition air as part of the primary ventilation system of the buildings. These air handling systems often include multiple fans and require backflow preventers or dampers to prevent air from flowing in the direction opposite normal air flow if one of the fans becomes disabled. Conventionally, there are three types of backflow dampers: manually operated backflow dampers, gravity actuated backflow dampers, and backflow dampers actuated by an electric motor. All of the typical backflow preventers tend to decrease the efficiency of the fans. The backflow preventers that are operated manually or by electric motor require additional parts and structure, which makes these backflow preventers more complicated and can disrupt the air flowing through the fans. The gravity actuated backflow preventers require that the air flow of the fan be strong enough to overcome the gravitational force of the dampers to open or close the backflow preventer. This required force reduces the efficiency of the fans in the air handling system.